Process for direct steam injection heating of oil sands slurry streams such as bitumen froth

Abstract

In the field of oil sands processing, a process for heating an oil sands slurry stream such as bitumen froth containing bitumen and water and having variable heating requirements includes injecting steam directly into the froth at a steam pressure through a plurality of nozzles to achieve sonic steam flow; operating the plurality of the nozzles to vary steam injection by varying a number of the nozzles through which the injecting of the steam occurs in response to the variable heating requirements; and subjecting the oil sands slurry stream to backpressure sufficient to enable sub-cooling relative to the boiling point of water. A corresponding system is also provided.

The invention claimed is: 
     
       1. A process for heating an oil sands bitumen froth stream that includes bitumen and water and having variable heating requirements, comprising:
 injecting steam directly into the oil sands bitumen froth stream at a steam pressure through a plurality of nozzles, wherein the injecting of the steam and the size and configuration of the nozzles are provided to achieve sonic steam flow and wherein the nozzles are positioned such that steam jet plumes extend into the oil sands bitumen froth stream while avoiding impingement on adjacent walls and such that adjacent steam jet plumes do not join; 
 operating the plurality of the nozzles to vary steam injection by varying a number of the nozzles through which the injecting of the steam occurs in response to the variable heating requirements for the oil sands bitumen froth stream; 
 subjecting the oil sands bitumen froth stream to backpressure downstream of the steam injection, sufficient to enable sub-cooling relative to the boiling point of water. 
 
     
     
       2. The process of  claim 1 , wherein the steam pressure is at least about 150 psig. 
     
     
       3. The process of  claim 1 , wherein the steam pressure is at least about 300 psig. 
     
     
       4. The process of  claim 1 , wherein the steam is superheated steam. 
     
     
       5. The process of  claim 1 , wherein the nozzles are each sized to have a throat diameter up to about 15 mm. 
     
     
       6. The process of  claim 1 , wherein the nozzles are each sized to have a throat diameter up to about 10 mm. 
     
     
       7. The process of  claim 1 , wherein the nozzles are sized and configured to each operate as an orifice and the sonic steam flow is provided according to orifice flow requirements. 
     
     
       8. The process of  claim 1 , wherein the nozzles are sized and configured to each operate as a pipe and the sonic steam flow is provided according to pipe flow requirements. 
     
     
       9. The process of  claim 1 , wherein at least a portion of the backpressure is provided by static pressure downstream of the injection of the steam. 
     
     
       10. The process of  claim 9 , wherein the static pressure is provided by a stand pipe to a holding tank inlet. 
     
     
       11. The process of  claim 1 , wherein at least a portion of the backpressure is provided by tank pressurization downstream of the injection of the steam. 
     
     
       12. The process of  claim 1 , wherein at least a portion of the backpressure is provided by at least one valve device downstream of the injection of the steam. 
     
     
       13. The process of  claim 1 , wherein at least a portion of the backpressure is provided by at least one pipeline configuration downstream of the injection of the steam. 
     
     
       14. The process of  claim 1 , wherein the backpressure is provided to enable the sub-cooling of the oil sands bitumen froth stream of at least 10° C. relative to the boiling point of water. 
     
     
       15. The process of  claim 1 , wherein the backpressure is provided to enable the sub-cooling of the oil sands bitumen froth stream of at least 20° C. relative to the boiling point of water. 
     
     
       16. The process of  claim 1 , comprising determining the variable heating requirements of the oil sands bitumen froth based on variable temperature. 
     
     
       17. The process of  claim 1 , comprising determining the variable heating requirements of the oil sands bitumen froth based on variable composition thereof. 
     
     
       18. The process of  claim 1 , comprising determining the variable heating requirements of the oil sands bitumen froth based on variable water content thereof. 
     
     
       19. The process of  claim 1 , comprising serially performing the injecting of the steam into the oil sands bitumen froth stream in a plurality of direct injection steam heaters arranged in series. 
     
     
       20. The process of  claim 1 , comprising performing the injecting of the steam into the oil sands bitumen froth stream in a plurality of direct injection steam heaters arranged in parallel. 
     
     
       21. The process of  claim 1 , wherein bitumen froth stream is derived from a primary separation vessel selected from at least one of an inclined plate settling vessel, a gravity settling vessel, a centrifuge and a cyclone. 
     
     
       22. The process of  claim 1 , wherein the injecting of the steam forms steam jets co-directionally with flow of the oil sands bitumen froth stream. 
     
     
       23. The process of  claim 1 , wherein the backpressure is provided sufficient to enable sub-cooling relative to the boiling point of a low boiling point component having a lower boiling point than water. 
     
     
       24. The process of  claim 23 , wherein the low boiling point component is a light hydrocarbon. 
     
     
       25. The process of  claim 1 , comprising pumping the oil sands bitumen froth stream through a supply pump at a sufficient pressure to allow the backpressure. 
     
     
       26. The process of  claim 1 , further comprising supplying heated oil sands bitumen froth to a storage tank. 
     
     
       27. The process of  claim 26 , wherein the storage tank comprises a bitumen froth inlet for supplying the heated oil sands bitumen froth thereto and controlling aeration of the heated oil sands bitumen froth. 
     
     
       28. The process of  claim 27 , wherein the bitumen froth inlet comprises a perforated pipe extending downward from an upper portion of the storage tank to a lower portion of the storage tank below a liquid level in the storage tank. 
     
     
       29. The process of  claim 27 , wherein the bitumen froth inlet comprises a sloped launder extending from above tank high level to below tank low level. 
     
     
       30. The process of  claim 29 , further comprising supplying a water wash into the storage tank at or proximate an upper part of the sloped launder. 
     
     
       31. The process of  claim 26 , comprising recirculating a portion of the heated oil sands bitumen froth as a recycled bitumen froth stream back into the oil sands bitumen froth stream upstream of the steam injection. 
     
     
       32. The process of  claim 26 , wherein the storage tank is configured to be atmospheric pressure. 
     
     
       33. The process of  claim 26 , wherein the storage tank is configured to be pressurized. 
     
     
       34. The process of  claim 1 , further comprising supplying heated oil sands bitumen froth to a froth deaerator vessel. 
     
     
       35. The process of  claim 34 , wherein the froth deaerator vessel is configured to be pressurized with purge gas. 
     
     
       36. The process of  claim 34 , wherein the froth deaerator vessel comprises a sloped launder inlet extending from above liquid level to below liquid level and being configured for inletting the oil sands bitumen froth. 
     
     
       37. The process of  claim 34 , wherein the froth deaerator vessel comprises a perforated pipe inlet extending downward from an upper portion of a storage tank to a lower portion of the storage tank below a liquid level in the deaerator vessel. 
     
     
       38. The process of  claim 1 , further comprising supplying heated oil sands bitumen froth to a froth slurry column. 
     
     
       39. The process of  claim 38 , wherein the froth slurry column comprises an inlet. 
     
     
       40. The process of  claim 39 , wherein the inlet comprises a flow restriction, a valve or a nozzle. 
     
     
       41. The process of  claim 38 , further comprising returning a portion of the heated oil sands bitumen froth back into the froth slurry column. 
     
     
       42. The process of  claim 1 , comprising controlling the nozzles and monitoring temperature of heated oil sands bitumen froth stream using a temperature control device connected. 
     
     
       43. The process of  claim 1 , wherein the nozzles are positioned and nozzle orifices are sized such that an envelope of condensate and process fluid surrounding the steam jet plumes extend into the oil sands bitumen froth stream while avoiding impingement on the adjacent walls. 
     
     
       44. The process of  claim 1 , wherein the oil sands bitumen froth stream is an underflow tailings stream from a froth separation vessel from a solvent froth treatment operation. 
     
     
       45. The process of  claim 44 , wherein the solvent in the froth treatment operation is paraffinic solvent. 
     
     
       46. The process of  claim 1 , wherein the oil sands bitumen froth stream is heated up to 130° C. 
     
     
       47. The process of  claim 1 , wherein the oil sands bitumen froth stream is heated above 95° C. and up to 130° C. 
     
     
       48. A process for heating an oil sands bitumen froth stream that includes bitumen and water and having variable heating requirements, comprising: injecting steam directly into the oil sands bitumen froth stream at a steam pressure through a plurality of nozzles, wherein the injecting of the steam and the size and configuration of the plurality of nozzles are provided to achieve sonic steam flow, and wherein adjacent nozzles of the plurality of nozzles are positioned such that steam jet plumes extend into the oil sands bitumen froth stream while avoiding impingement on adjacent walls;
 varying steam injection through the nozzles in response to the variable heating requirements for the oil sands bitumen froth stream; 
 subjecting the oil sands bitumen froth stream to backpressure downstream of the steam injection, sufficient to enable sub-cooling relative to the boiling point of water. 
 
     
     
       49. The process of  claim 48 , wherein the steam pressure is at least about 150 psig. 
     
     
       50. The process of  claim 48 , wherein the steam pressure is at least about 300 psig. 
     
     
       51. The process of  claim 48 , wherein the nozzles are each sized to have a throat diameter up to about 15 mm. 
     
     
       52. The process of  claim 48 , wherein the nozzles are each sized to have a throat diameter up to about 10 mm. 
     
     
       53. The process of  claim 48 , wherein the backpressure is provided to enable the sub-cooling of the oil sands bitumen froth stream of at least 10° C. relative to the boiling point of water. 
     
     
       54. The process of  claim 48 , wherein the backpressure is provided to enable the sub-cooling of the oil sands bitumen froth stream of at least 20° C. relative to the boiling point of water. 
     
     
       55. The process of  claim 48 , wherein the oil sands bitumen froth stream is an underflow tailings stream from a froth separation vessel from a solvent froth treatment operation. 
     
     
       56. The process of  claim 55 , wherein the solvent in the froth treatment operation is paraffinic solvent. 
     
     
       57. The process of  claim 48 , wherein the oil sands bitumen froth stream is heated up to 130° C. 
     
     
       58. The process of  claim 48 , comprising serially performing the injecting of the steam into the oil sands bitumen froth stream in a plurality of direct injection steam heaters arranged in series. 
     
     
       59. The process of  claim 48 , comprising performing the injecting of the steam into the oil sands bitumen froth stream in a plurality of direct injection steam heaters arranged in parallel.